The long range interests of this laboratory center on mechanisms of biogenesis of the lipopolysaccharide of Salmonella typhimurium and its assembly into the outer membrane. This study focuses on translocation of lipopolysaccharide from inner to outer membrane and proposes a novel genetic approach to identify components of a postulated translocation machinery. Temperature-conditional mutants in lipopolysaccharide translocation will be isolated by only by a newly developed method for immunoaffinity enrichment. Such mutants have not previously been obtained. Physiological and biochemical characterization will determine effects of mutant expression on growth, cell envelope structure and outer membrane structure, function and assembly. Localization of lipopolysaccharide produced at nonpermissive temperature will help define discrete steps in the translocation pathway. Mutations will be genetically mapped by standard techniques and extragenic suppressor mutations will be sought in order to identify additional interacting components of the translocation machinery. In the long range, gene products and their functions will be identified by molecular cloning and other approaches.